compat: Add simplified merge sort implementation from glibc

diff --git a/parse-options.h b/parse-options.h
index 2b8e7624d67b5796d9e1b38cf65700c5471b98ff..102ac31fb727acfdc3c2159e1525c7bcca94e1ef 100644 (file)
--- a/parse-options.h
+++ b/parse-options.h
@@ -2,9 +2,15 @@
 #define PARSE_OPTIONS_H
 
 enum parse_opt_type {
+       /* special types */
        OPTION_END,
        OPTION_GROUP,
-       OPTION_BOOLEAN,
+       /* options with no arguments */
+       OPTION_BIT,
+       OPTION_BOOLEAN, /* _INCR would have been a better name */
+       OPTION_SET_INT,
+       OPTION_SET_PTR,
+       /* options with arguments (usually) */
        OPTION_STRING,
        OPTION_INTEGER,
        OPTION_CALLBACK,
@@ -16,11 +22,54 @@ enum parse_opt_flags {
 
 enum parse_opt_option_flags {
        PARSE_OPT_OPTARG  = 1,
+       PARSE_OPT_NOARG   = 2,
+       PARSE_OPT_NONEG   = 4,
+       PARSE_OPT_HIDDEN  = 8,
 };
 
 struct option;
 typedef int parse_opt_cb(const struct option *, const char *arg, int unset);
 
+/*
+ * `type`::
+ *   holds the type of the option, you must have an OPTION_END last in your
+ *   array.
+ *
+ * `short_name`::
+ *   the character to use as a short option name, '\0' if none.
+ *
+ * `long_name`::
+ *   the long option name, without the leading dashes, NULL if none.
+ *
+ * `value`::
+ *   stores pointers to the values to be filled.
+ *
+ * `argh`::
+ *   token to explain the kind of argument this option wants. Keep it
+ *   homogenous across the repository.
+ *
+ * `help`::
+ *   the short help associated to what the option does.
+ *   Must never be NULL (except for OPTION_END).
+ *   OPTION_GROUP uses this pointer to store the group header.
+ *
+ * `flags`::
+ *   mask of parse_opt_option_flags.
+ *   PARSE_OPT_OPTARG: says that the argument is optionnal (not for BOOLEANs)
+ *   PARSE_OPT_NOARG: says that this option takes no argument, for CALLBACKs
+ *   PARSE_OPT_NONEG: says that this option cannot be negated
+ *   PARSE_OPT_HIDDEN this option is skipped in the default usage, showed in
+ *                    the long one.
+ *
+ * `callback`::
+ *   pointer to the callback to use for OPTION_CALLBACK.
+ *
+ * `defval`::
+ *   default value to fill (*->value) with for PARSE_OPT_OPTARG.
+ *   OPTION_{BIT,SET_INT,SET_PTR} store the {mask,integer,pointer} to put in
+ *   the value when met.
+ *   CALLBACKS can use it like they want.
+ */
 struct option {
        enum parse_opt_type type;
        int short_name;
@@ -31,14 +80,15 @@ struct option {
 
        int flags;
        parse_opt_cb *callback;
-       /* holds default value for PARSE_OPT_OPTARG,
-          though callbacks can use it like they want */
        intptr_t defval;
 };
 
 #define OPT_END()                   { OPTION_END }
 #define OPT_GROUP(h)                { OPTION_GROUP, 0, NULL, NULL, NULL, (h) }
+#define OPT_BIT(s, l, v, h, b)      { OPTION_BIT, (s), (l), (v), NULL, (h), 0, NULL, (b) }
 #define OPT_BOOLEAN(s, l, v, h)     { OPTION_BOOLEAN, (s), (l), (v), NULL, (h) }
+#define OPT_SET_INT(s, l, v, h, i)  { OPTION_SET_INT, (s), (l), (v), NULL, (h), 0, NULL, (i) }
+#define OPT_SET_PTR(s, l, v, h, p)  { OPTION_SET_PTR, (s), (l), (v), NULL, (h), 0, NULL, (p) }
 #define OPT_INTEGER(s, l, v, h)     { OPTION_INTEGER, (s), (l), (v), NULL, (h) }
 #define OPT_STRING(s, l, v, a, h)   { OPTION_STRING,  (s), (l), (v), (a), (h) }
 #define OPT_CALLBACK(s, l, v, a, h, f) \
@@ -55,4 +105,15 @@ extern int parse_options(int argc, const char **argv,
 extern NORETURN void usage_with_options(const char * const *usagestr,
                                         const struct option *options);
 
+/*----- some often used options -----*/
+extern int parse_opt_abbrev_cb(const struct option *, const char *, int);
+
+#define OPT__VERBOSE(var)  OPT_BOOLEAN('v', "verbose", (var), "be verbose")
+#define OPT__QUIET(var)    OPT_BOOLEAN('q', "quiet",   (var), "be quiet")
+#define OPT__DRY_RUN(var)  OPT_BOOLEAN('n', "dry-run", (var), "dry run")
+#define OPT__ABBREV(var)  \
+       { OPTION_CALLBACK, 0, "abbrev", (var), "n", \
+         "use <n> digits to display SHA-1s", \
+         PARSE_OPT_OPTARG, &parse_opt_abbrev_cb, 0 }
+
 #endif